A Pair of Rectangular Slots for Bandwidth Improvement of Microstrip Antenna Fed by Proximity Coupling

In this paper, a pair of rectangular slots is employed to improve the bandwidth characteristic of microstrip antenna. A proximity coupling technique is employed to feed the proposed antenna, which is also useful for improving the bandwidth. To demonstrate the advantage of utilizing a pair of rectangular slots in bandwidth improvement, three configurations of microstrip antenna are investigated. Each configuration which is designed to operate at the frequency of 5.3 GHz for Unmanned Aerial Vehicle (UAV) communication is deployed on two layers of 1.6 mm thick NPC H220A dielectric substrate. The first configuration is a conventional microstrip antenna which is fed directly by a microstrip line. Meanwhile, the second and the third configurations are modified from the first one, whereby both are fed by proximity coupling techniques. A pair of rectangular slots is incorporated upon the radiating patch of third configuration. The characterization results show that the third configuration achieves the widest bandwidth among others, in which the measured bandwidths are 242 MHz, 276 MHz, and 309 MHz for conventional, proximity coupling, and proximity coupling with a pair of rectangular slots, respectively. Furthermore, gain and radiation pattern of each configuration are almost similar one each other and suitable for the desirable application.